Migraine after stellate ganglion block: A case report

Key Clinical Message Stellate ganglion block‐induced ipsilateral migraines are rare. We present a typical case detailing its developmental process. Abnormalities in the autonomic nervous system control and vascular and neural mechanisms may play crucial roles in the manifestation of these migraines. Postprocedural migraines necessitate anesthesiologists' awareness during stellate ganglion blocks.


| INTRODUCTION
The stellate ganglion is formed by the fusion of the inferior cervical and first thoracic sympathetic ganglion.It lies anterior to the transverse process of C7 and superior border of the first rib and posteromedial to the carotid artery.The ganglion is covered by prevertebral fascia, which is a layer of deep cervical fascia.Sympathetic fibers for the head, neck, thoracic viscera, and upper limbs synapse in the stellate ganglion.Therefore, the ganglion is a target location to block for the treatment of pain and other conditions affecting these anatomical areas. 1 A stellate ganglion block (SGB) can be performed safely using anatomical landmarks, or under fluoroscopy or ultrasound guidance.The SGB target area is usually the middle cervical sympathetic ganglion on the surface of the longus colli at the level of C6, with the injectate flowing caudally.
Currently, ultrasound-guided SGB, performed to safely block the sympathetic ganglia innervating the head, neck, face, and upper limbs, functions through vasodilation of the target area.It can also be used for systemic diseases such as insomnia and autonomic imbalance. 2,3Previous studies confirmed that cerebrovascular resistance can be sustainably reduced, cerebral blood flow can be moderately increased, and cerebrovascular spasms can improve after cervical sympathectomy or sympathetic ganglion block. 1 These findings are consistent with those of animal studies. 4,5Other studies have shown that reactions, such as decreased cerebral vascular tone, are present in patients with abnormal intracranial physiological conditions, such as cerebral vasospasm, 1,6 and in those without such conditions. 7ur literature search revealed only two other patients with migraine episodes similar to those in the current case. 8,9However, unlike our patient, the two patients experienced migraines accompanied by an aura, and the migraines persisted for several months.Therefore, this report presents our case of a patient who experienced migraines without auras after undergoing SGB for insomnia.
A mid-40s man was admitted with complaints of difficulty falling asleep and insomnia.His Pittsburgh Sleep Quality Index (PSQI) 8 score was 12, signifying poor sleep quality, and his Insomnia Severity Index (ISI) 9 score was 19, indicating clinical insomnia.Past medical and family histories were normal.Despite taking the sedative zolpidem for over 5 years, he found traditional medication for insomnia ineffective.He urgently needed to stop taking the medication and desired non-pharmacological treatment to address the sleep difficulties.After obtaining procedural informed consent from the patient, we scheduled an ultrasound-guided SGB.The general procedure for SGB is discussed in the following section.

| Procedure for SGB
The patient is positioned supine in the anesthesia outpatient treatment room with the head turned to the left and the neck fully exposed.After standard disinfection, a high-frequency linear array probe for color Doppler ultrasound identifies the right C7 vertebrate's transverse process at the cricoid cartilage plane, and moved slightly toward the midline.Various anatomical structures like the carotid artery, internal jugular vein, thyroid gland, trachea, esophagus, and longus colli/cervicis are pinpointed.The stellate ganglion is located on the longus colli/cervicis surface (Figure 1).Under ultrasound guidance, the SGB is performed using an in-plane injection method.The injection needle's tip halts after passing through the prevertebral fascia and reaching the longus colli/cervicis surface, followed by injecting 4 mL of 0.25% ropivacaine.Successful block is confirmed by the presence of Horner's syndrome signs including ipsilateral myosis, ptosis, enophthalmos, nasal congestion, and facial anhidrosis.

| Post procedure
Thirty minutes following SGB, our patient experienced a severe pulsatile headache in the right temporal lobe area (temple) accompanied by nausea.Vital signs were as follows: HR, 93 bpm; BP, 126/69 mm Hg; and SpO 2 , 99%.Although the pain was slightly reduced after oral administration of a nonsteroidal anti-inflammatory drug (ibuprofen), the headache persisted for over 20 h.The patient underwent head magnetic resonance imaging (MRI) the next day, which was unremarkable, showing no organic lesions in the intracranial area (Figure 2).On the following day, a neurologist conducted a consultation with the patient.During the subsequent 2 weeks, the patient experienced 2-3 similar migraine episodes per day and was otherwise feeling well between these episodes.Physical signs and symptoms were consistent with migraine without aura (International Headache Society [IHS] definition 10 ) as defined by a neurologist.Approximately 2½ weeks later (4½ weeks from migraine onset), the patient returned for a follow-up appointment.As of that appointment, the patient has had no further migraines.Migraine is a complex neurological disease characterized by recurrent episodes of moderate-to-severe pain intensity headaches. 11Despite its prevalence, the underlying pathophysiological mechanisms remain elusive. 11,12he current patient had no history of migraines or other chronic headaches.The signs and symptoms of the ipsilateral migraine without aura developed after ultrasound-guided SGB for insomnia.Our literature search revealed two other cases in which the patients experienced migraines after SGB. 13,14Those patients had auras accompanying the migraines, and the migraines persisted for several months.The differences between those patients and the current patient are shown in Table 1.There are differences in volume of local anesthetics between these

First patient 11
Second patient patients.The drugs and concentrations used were different which suggest this phenomenon might be dose and volume independent.
Our patient experienced an ipsilateral migraine after undergoing a right stellate nerve block.Upon initial onset, we considered that the migraine may have resulted from the sympathetic block causing vasodilation of the ipsilateral head vasculature.However, after the disappearance of the acute sympathetic inhibition, the migraines persisted intermittently and lasted for 2 weeks before disappearing.The two previously reported patients experienced post sympathetic block migraines which lasted intermittently for several months (Table 1) before disappearing.We speculate that the mechanical expansion of vascular smooth muscle cells may activate nociceptors around blood vessels and release pain-promoting and proinflammatory substances.Thus, after complete recovery from vasodilation, intermittent migraines can persist.

| CONCLUSION
In conclusion, ipsilateral migraines induced by SGB are rare.Therefore, the exact mechanisms underlying their occurrence remain unclear.We suggest that abnormalities in autonomic nervous system control and vascular and neural mechanisms contribute to migraine occurrence.More reported cases are required to further elucidate the mechanisms of SGB-induced migraines.

F I G U R E 1
Short axis sonogram at C7. (A, B) The transducer is moved slowly laterally and cephalad until the characteristic posterior tubercle of C7 appears in the image.The solid arrow shows the anterior vertebral fascia.The stellate ganglion is located on the deep surface of the anterior fascia and the surface of the longus colli muscle.ASM, anterior scalene muscle; CCA, common carotid artery; IJV, internal jugular vein; Lcol, longus colli muscle; MSM, middle scalene muscle; N, nerve; pt, posterior tubercle; SCM, sternocleidomastoid muscle; SG, stellate ganglion; VA, vertebral artery; VV, vertebral vein.

F I G U R E 2
Brain MRI.Axial section of the lateral ventricle shows no obvious abnormalities.(A) T2-weighted image (T2WI); (B) T1-weighted image (T1WI).L, left; MRI, magnetic resonance imaging; R, right.T A B L E 1 Cases of migraine attacks after SGB.